In a known pushbutton contact of the above mentioned kind described in DE-OS No. 27 43 307, a disk having cam surfaces can be secured on the actuating member and can cooperate with detent means retained on a ring and insertable into the fixed part of the pushbutton contactor, so that a monostable pushbutton can be transformed into a bistable push-pull switch.
This arrangement has the disadvantage that a stock of additional parts must be maintained for use when they may be needed. In addition, disassembly of the entire device is required, since the detent means inside the device are not accessible from the outside. Thus when changing the intermittent contact action to a locking function and vice versa, the actual switching member must be removed from the actuating member. This increases installation costs.